5 Pollution and its Factors part 1
INTRODUCTION
Pollution may be defined as an undesirable change in the physical, chemical or biological
characteristics of air, water and land that may be harmful to human life and other animals,
living conditions, industrial processes and cultural assets. Pollution can be natural or manmade. The agents that pollute are called pollutants.
Pollutants
Pollutants are by-products of man’s action. The important pollutants are summarised
below:
• Deposited matter—Soot, smoke, tar or dust and domestic wastes.
• Gases—CO, nitrogen oxides, sulphur oxides, halogens (chlorine, bromine and iodine).
• Metals—Lead, zinc, iron and chromium.
• Industrial pollutants—Benzene, ether, acetic acid etc., and cyanide compounds.
• Agriculture pollutants—Pesticides, herbicides, fungicides and fertilizers.
• Photochemical pollutants—Ozone, oxides of nitrogen, aldehydes, ethylene,
photochemical smog and proxy acetyl nitrate.
• Radiation pollutants—Radioactive substances and radioactive fall-outs of the
nuclear test.
Classification of Pollutants
On the basis of natural disposal, pollutants are of two types:
(i) Non-degradable pollutants
These are the pollutants, which degrade at a very slow pace by the natural biological
processes. These are inorganic compounds such as salts (chlorides), metallic oxides waste
producing materials and materials like, aluminium cans, mercuric salts and even DDT.
These continue to accumulate in the environment.
(ii) Biodegradable pollutants
These include domestic sewage that easily decomposes under natural processes and can
be rapidly decomposed by natural/ artificial methods. These cause serious problems when
accumulated in large amounts as the pace of deposition exceeds the pace of decomposition
of disposal.
On the basis of the form in which they persist after their release into the environment,
pollutants can be categorized under two types:
(i) Primary pollutants : These include those substances, which are emitted directly
from some identifiable sources. This include-
(a) Sulphur compounds: SO2, SO3, H2S produced by the oxidation of fuel.
(b) Carbon compounds: Oxides of carbon (CO+CO2) and hydrocarbons.
(c) Nitrogen compounds: NO2 and NH3.
(d) Halogen compounds: Hydrogen fluoride (HF) and hydrochloric acid (HCl).
(e) Particles of different size and substances: These are found suspended in air.
The fine particles below the diameter of 100u are more abundant and include
particles of metals, carbon, tar, pollen, fungi, bacteria, silicates and others.
(ii) Secondary pollutants. The secondary pollutants are produced by the combination
of primary emitted pollutants. in the atmosphere. In bright sunlight, a photochemical
reaction occurs between nitrogen oxides; oxygen and waste hydrocarbons from
gasoline that forms peroxyacetyle nitrate (PAN) and ozone (O3), Both of them are
toxic components of smog and cause smarting eyes and lung damage.
(iii) Smog. The fog deposited with smoke and chemical fumes forms a dark and thick
covering, the smog. Smog is very common in almost all the industrial areas as the
smog is trapped for many days by the stagnant air. It is harmful both for animals
and plants.
AIR POLLUTION
The WHO defines air pollution as the presence of materials in the air in such
concentration which are harmful to man and his environment. A number of ingredients find
their way in the air and these are mostly gases, which rapidly spread over wide areas.
SOURCES OF AIR POLLUTION
Various sources of air pollution are fossil fuels, industries, agricultural activities, wars,
natural causes arid emissions from vehicles.
(i) Burning Fossil Fuels
Burning of wood, charcoal and other fossil fuels causes air pollution by the release of
carbon dioxide (CO2), carbon sulphur dioxide etc. Petroleum consists mainly of hydrocarbons,
sulphur and nitrogen.
(ii) Emissions from Automobiles
Vehicles are mainly responsible for more than 80% of total air pollution.
The major pollutants released from automobiles, locomotives, aircraft etc., include CO, unburnt
hydrocarbons and nitrogen oxide.
(iii) Industries
Paper and pulpfactories, petroleum refineries, fertilizer plants, and steel industries,
thermal power plants are the main sources of air pollution. They add various harmful gases
like CO, SO3, NO, Hydrocarbons etc., to the atmosphere. Textile factories release cotton dust
into the air. Cities experiencing this type of pollution are Kanpur, Surat and Ahmedabad.
The pesticide and insecticide industries are posing serious threat to the environment. Food
processing industries and tanneries emit offensive odors. Release of poisonous gases from
accidents also poses serious threats. e.g. Bhopal Gas Tragedy in which methyl isocynate
(MIC) gas leakage killed several people. In Tokyo, about 34 tones of carbon particles mixed
with other suspended particles settle per square kilometer every day.
(iv) Agricultural Activities
Spraying of insecticides and weedicides also cause air pollution. These, when inhaled
create severe problems to both animals and man.
(v) Wars
Various forms of explosives used in war pollute the air by releasing poisonous gases.
This greatly disturbs the ecology of the area. Nuclear explosions pollute air by radioactive
rays. The effects of nuclear explosions on Hiroshima and Nagasaki are well-known examples.
(vi) Natural Causes
Gas emissions from active volcanoes, marsh gas, spores of fungi and pollens are the
natural causes of air pollution.
COMMON AIR POLLUTANTS
Air pollutants are of two main types ~gaseous and particulate. Oxides of carbon. Nitrogen
and sulphur are gaseous pollutants. Particulate pollutants may be solid or liquid particles,
larger particles settle down quickly viz., sand and water droplets whereas small dust particles
remain suspended in air for a long time. These are added into the atmosphere by the
processes of blasting, drilling, crushing, grinding and mixing.
(i) Carbon Dioxide
CO
2 content of air has increased by 20% during the last century. CO2 causes nausea
and headache. It’s increase in the air may cause green house effect, rise in the atmospheric
temperature. This may melt the polar ice resulting in rise in level of oceans and flooding
of coastal regions.
(ii) Carbon Monoxide
It is a very poisonous gas and is produced by incomplete combustion of fuel. If inhaled.
it combines with hemoglobin and reduces its oxygen-carrying capacity. This leads to laziness,
reduced vision and death.
Pollution may be defined as an undesirable change in the physical, chemical or biological
characteristics of air, water and land that may be harmful to human life and other animals,
living conditions, industrial processes and cultural assets. Pollution can be natural or manmade. The agents that pollute are called pollutants.
Pollutants
Pollutants are by-products of man’s action. The important pollutants are summarised
below:
• Deposited matter—Soot, smoke, tar or dust and domestic wastes.
• Gases—CO, nitrogen oxides, sulphur oxides, halogens (chlorine, bromine and iodine).
• Metals—Lead, zinc, iron and chromium.
• Industrial pollutants—Benzene, ether, acetic acid etc., and cyanide compounds.
• Agriculture pollutants—Pesticides, herbicides, fungicides and fertilizers.
• Photochemical pollutants—Ozone, oxides of nitrogen, aldehydes, ethylene,
photochemical smog and proxy acetyl nitrate.
• Radiation pollutants—Radioactive substances and radioactive fall-outs of the
nuclear test.
Classification of Pollutants
On the basis of natural disposal, pollutants are of two types:
(i) Non-degradable pollutants
These are the pollutants, which degrade at a very slow pace by the natural biological
processes. These are inorganic compounds such as salts (chlorides), metallic oxides waste
producing materials and materials like, aluminium cans, mercuric salts and even DDT.
These continue to accumulate in the environment.
(ii) Biodegradable pollutants
These include domestic sewage that easily decomposes under natural processes and can
be rapidly decomposed by natural/ artificial methods. These cause serious problems when
accumulated in large amounts as the pace of deposition exceeds the pace of decomposition
of disposal.
On the basis of the form in which they persist after their release into the environment,
pollutants can be categorized under two types:
(i) Primary pollutants : These include those substances, which are emitted directly
from some identifiable sources. This include-
(a) Sulphur compounds: SO2, SO3, H2S produced by the oxidation of fuel.
(b) Carbon compounds: Oxides of carbon (CO+CO2) and hydrocarbons.
(c) Nitrogen compounds: NO2 and NH3.
(d) Halogen compounds: Hydrogen fluoride (HF) and hydrochloric acid (HCl).
(e) Particles of different size and substances: These are found suspended in air.
The fine particles below the diameter of 100u are more abundant and include
particles of metals, carbon, tar, pollen, fungi, bacteria, silicates and others.
(ii) Secondary pollutants. The secondary pollutants are produced by the combination
of primary emitted pollutants. in the atmosphere. In bright sunlight, a photochemical
reaction occurs between nitrogen oxides; oxygen and waste hydrocarbons from
gasoline that forms peroxyacetyle nitrate (PAN) and ozone (O3), Both of them are
toxic components of smog and cause smarting eyes and lung damage.
(iii) Smog. The fog deposited with smoke and chemical fumes forms a dark and thick
covering, the smog. Smog is very common in almost all the industrial areas as the
smog is trapped for many days by the stagnant air. It is harmful both for animals
and plants.
AIR POLLUTION
The WHO defines air pollution as the presence of materials in the air in such
concentration which are harmful to man and his environment. A number of ingredients find
their way in the air and these are mostly gases, which rapidly spread over wide areas.
SOURCES OF AIR POLLUTION
Various sources of air pollution are fossil fuels, industries, agricultural activities, wars,
natural causes arid emissions from vehicles.
(i) Burning Fossil Fuels
Burning of wood, charcoal and other fossil fuels causes air pollution by the release of
carbon dioxide (CO2), carbon sulphur dioxide etc. Petroleum consists mainly of hydrocarbons,
sulphur and nitrogen.
(ii) Emissions from Automobiles
Vehicles are mainly responsible for more than 80% of total air pollution.
The major pollutants released from automobiles, locomotives, aircraft etc., include CO, unburnt
hydrocarbons and nitrogen oxide.
(iii) Industries
Paper and pulpfactories, petroleum refineries, fertilizer plants, and steel industries,
thermal power plants are the main sources of air pollution. They add various harmful gases
like CO, SO3, NO, Hydrocarbons etc., to the atmosphere. Textile factories release cotton dust
into the air. Cities experiencing this type of pollution are Kanpur, Surat and Ahmedabad.
The pesticide and insecticide industries are posing serious threat to the environment. Food
processing industries and tanneries emit offensive odors. Release of poisonous gases from
accidents also poses serious threats. e.g. Bhopal Gas Tragedy in which methyl isocynate
(MIC) gas leakage killed several people. In Tokyo, about 34 tones of carbon particles mixed
with other suspended particles settle per square kilometer every day.
(iv) Agricultural Activities
Spraying of insecticides and weedicides also cause air pollution. These, when inhaled
create severe problems to both animals and man.
(v) Wars
Various forms of explosives used in war pollute the air by releasing poisonous gases.
This greatly disturbs the ecology of the area. Nuclear explosions pollute air by radioactive
rays. The effects of nuclear explosions on Hiroshima and Nagasaki are well-known examples.
(vi) Natural Causes
Gas emissions from active volcanoes, marsh gas, spores of fungi and pollens are the
natural causes of air pollution.
COMMON AIR POLLUTANTS
Air pollutants are of two main types ~gaseous and particulate. Oxides of carbon. Nitrogen
and sulphur are gaseous pollutants. Particulate pollutants may be solid or liquid particles,
larger particles settle down quickly viz., sand and water droplets whereas small dust particles
remain suspended in air for a long time. These are added into the atmosphere by the
processes of blasting, drilling, crushing, grinding and mixing.
(i) Carbon Dioxide
CO
2 content of air has increased by 20% during the last century. CO2 causes nausea
and headache. It’s increase in the air may cause green house effect, rise in the atmospheric
temperature. This may melt the polar ice resulting in rise in level of oceans and flooding
of coastal regions.
(ii) Carbon Monoxide
It is a very poisonous gas and is produced by incomplete combustion of fuel. If inhaled.
it combines with hemoglobin and reduces its oxygen-carrying capacity. This leads to laziness,
reduced vision and death.
(iii) Oxides of Nitrogen
These include NO and NO
2, which are released by automobiles and chemical industries
as waste gases and also by burning of materials. These are harmful and lower the oxygen
carrying capacity of blood.
(iv) Oxides of Sulphur
SO
2 and SO3 are produced by burning of coal and petroleum and are harmful to buildings,
clothing, plants and animals. High concentration of SO2 causes chlorosis (yellowing of leaves),
plasmolysis, damage to mucous membrane and metabolic inhibition. SO2 and SO3 react with
water to form Sulphuric and sulphurous acids. These may precipitate as rain or snow
producing acid rain or acid precipitation.
(v) Photochemical Oxidants
Formed by the photochemical reactions between primary pollutants, viz. oxides of
nitrogen and hydrocarbons. Nitrogen oxides in the presence of sunlight react with unburnt
hydrocarbons to form peroxyacyl nitrate (PAN), Ozone, aldehydes and some other complex
organic compounds in the air.
(vi) Hydrocarbons
These are unburnt discharges from incomplete combustion of fuel in automobiles. These
form PAN with nitrogen oxides, which is highly toxic.
(vii) Particulate Matter
Industries and automobiles release fine solid and liquid particles into the air. Fly ash
and soot from burning of coal, metal dust containing lead, chromium, nickel, cadmium, zinc
and mercury from metallurgical processes; cotton dust from textile mills; and pesticides
sprayed on crops are examples of particulate pollutants in the air. These are injurious to
respiratory tract.
(viii) Aerosols
Aerosols are chemicals released in the air in vapour form. These include fluorocarbon
(carbon compound having fluorine) present in emissions from the Jet aeroplanes. Aerosols
deplete the ozone layer. Thinning of ozone layer results in more harmful ultraviolet rays
reaching the earth, which are harmful to skin, and can lead to skin cancer also.
(ix) Radioactive Substances
These are released by nuclear explosions and explosives. These are extremely harmful
for health.
(x) Fluorides
Rocks, soils and. minerals containing fluorides release an extremely toxic gas called
hydrogen fluoride on heating. This gas is highly injurious to livestock and cattle.
POLLUTION IN INDIA
India supports a large network of factories and industries. These factories are generally
localized in eight or ten large industrial centres. These are also a great source of air as well
water pollution. To be on a safer side delocalisation of industries is the need of the time.
This would lead to an even distribution of pollutants and faster degeneration of pollutants.
The major pollutants coming out from these industries are -
(i) Industrial Pollutants. The common air pollutants from industries are SO2, CO,
CO
2, H2S and hydrocarbons together with dust, smoke and grit. These are produced
by the burning of coal and petroleum and by the combustion of lignite at thermal
power stations. The chemical industries release HCl, chlorine, nitrogen oxide and
oxides of copper, zinc, lead and arsenic.
The fertilizer factories at Gorakhpur and Ahmedabad; the steel industries at Bhilai,
Rourkela, Jamshedpur and Durgapur pollute the air with above-said gases.
(ii) Automobile Exhausts. Automobiles run by petrol and diesel produce CO, nitrogen
oxides and hydrocarbons. Hundreds and thousands tons of hydrocarbons and CO
are emitted into air daily. Metropolitan cities harbour lakhs and crores of
automobiles. Every gallon of petrol consumed by automobiles produces 3 pounds of
carbon monoxide and 15 pounds. of nitrogen oxide.
(iii) Ionizing Radiations from Radioactive Substances. Ionizing radiations include alpha,
beta particles and the gamma rays etc. These are produced by atomic explosions
and testing of atomic weapons.
Effects of Air Pollution
Effect on Plants
(i) SO2 causes chlorosis and also results in the death of cells and tissues.
(ii) Fluorides and PAN damage leafy vegetables such as lettuce and spinach.
(iii) Oxides of nitrogen and fluorides reduce crop yield.
(iv) Smog bleaches and blaze foliage of important leafy plants.
(v) Hydrocarbons cause premature yellowing, fall of leave and flower buds, discoloration
and curling of sepals and petals.
(vi) Smoke and dust cover the leaf surface and reduce photosynthetic capacity of plants.
(vii) Ozone damages cereals, fruits, and cotton crop.
Effect on Man
The effect of pollutants on animals and man are as follows-
(i) Ozone causes dryness of mucous membranes, changes eye vision, causes headache,
pulmonary congestion and oedema.
(ii) Ozone has been reported to produce chromosomal aberrations.
(iii) SO2 causes drying of mouth, scratchy throat, smarting eyes and disorders of
respiratory tract.
(iv) SO3, CO and NO2 diffuse into blood stream and reduce oxygen transport. CO
damages cardiovascular system. Hydrocarbons and other pollutants act, as
carcinogens and lead to different cancers.
(v) Cotton dust leads to respiratory disorders e.g. bronchitis and asthma.
(vi) Smoking of tobacco causes cancerous growth in lungs.
Change in Climate
CO
2 content of air is increasing due to deforestation and combustion of fuel. This
increase is affecting the composition and balance of gases in the atmosphere. Increase in
CO
2 concentration may increase the atmospheric temperature, producing green house effect
A rise of global temperature by more than 2-3 degrees may melt glaciers and polar ice. This
would lead to a rise in ocean level and consequent flooding and submergence of coastal
areas. Rainfall pattern may also change, affecting agricultural output in various regions of’
the world. Aerosols deplete the ozone layer in the stratosphere. Thinning of ozone layer
would permit more of the harmful ultraviolet rays to reach the earth. This may cause,
sunburn, blindness and inactivation of proteins, RNA, DNA and plant pigments.
Aesthetic Loss
Dust and smoke spoils the beauty of nature. Especially the mountain environments,
which serve as a great attraction for tourists. Foul odours emitted by industries, automobiles,
dirty drains and garbage heaps in cities are a great nuisance.
Control of Air Pollution
Following measures have been suggested to control air pollution-
(i) Some gases, which are more soluble in a particular liquid than air, for example,
ammonia in water, can be separated by dissolving in it
(ii) Particles larger than 50 mm are separated in gravity settling tanks. Using cyclone
collectors or electrostatic precipitators separates fine particles.
(iii) The height of chimneys should .be increased to the highest possible level to reduce
pollution at the ground level.
(iv) SO2 pollution can be controlled by extracting sulphur from the fuel before use.
(v) Pollution control laws should be enforced strictly.
(vi) Trees should be planted on the roadside, riverbanks, parks and’ open places as they
keep the environment fresh.
(vii) Population growth, which is the main cause of pollution should be checked.
(viii) Nuclear explosions should be restricted.
Water Pollution
Water is extremely essential for life, this common fact is known to all. It is required to
meet our basic needs in day to day life viz., cooking, drinking, bathing, disposal of sewage,
irrigation, generating electricity in power plants, cooling and manufacturing different products
in industries and the disposal of industrial wastes. During all these processes the undesirable
substances are added to the water resources to a great extent. This alters the basic chemistry
of water in rivers and streams.
<<< Previous Next >>>
These include NO and NO
2, which are released by automobiles and chemical industries
as waste gases and also by burning of materials. These are harmful and lower the oxygen
carrying capacity of blood.
(iv) Oxides of Sulphur
SO
2 and SO3 are produced by burning of coal and petroleum and are harmful to buildings,
clothing, plants and animals. High concentration of SO2 causes chlorosis (yellowing of leaves),
plasmolysis, damage to mucous membrane and metabolic inhibition. SO2 and SO3 react with
water to form Sulphuric and sulphurous acids. These may precipitate as rain or snow
producing acid rain or acid precipitation.
(v) Photochemical Oxidants
Formed by the photochemical reactions between primary pollutants, viz. oxides of
nitrogen and hydrocarbons. Nitrogen oxides in the presence of sunlight react with unburnt
hydrocarbons to form peroxyacyl nitrate (PAN), Ozone, aldehydes and some other complex
organic compounds in the air.
(vi) Hydrocarbons
These are unburnt discharges from incomplete combustion of fuel in automobiles. These
form PAN with nitrogen oxides, which is highly toxic.
(vii) Particulate Matter
Industries and automobiles release fine solid and liquid particles into the air. Fly ash
and soot from burning of coal, metal dust containing lead, chromium, nickel, cadmium, zinc
and mercury from metallurgical processes; cotton dust from textile mills; and pesticides
sprayed on crops are examples of particulate pollutants in the air. These are injurious to
respiratory tract.
(viii) Aerosols
Aerosols are chemicals released in the air in vapour form. These include fluorocarbon
(carbon compound having fluorine) present in emissions from the Jet aeroplanes. Aerosols
deplete the ozone layer. Thinning of ozone layer results in more harmful ultraviolet rays
reaching the earth, which are harmful to skin, and can lead to skin cancer also.
(ix) Radioactive Substances
These are released by nuclear explosions and explosives. These are extremely harmful
for health.
(x) Fluorides
Rocks, soils and. minerals containing fluorides release an extremely toxic gas called
hydrogen fluoride on heating. This gas is highly injurious to livestock and cattle.
POLLUTION IN INDIA
India supports a large network of factories and industries. These factories are generally
localized in eight or ten large industrial centres. These are also a great source of air as well
water pollution. To be on a safer side delocalisation of industries is the need of the time.
This would lead to an even distribution of pollutants and faster degeneration of pollutants.
The major pollutants coming out from these industries are -
(i) Industrial Pollutants. The common air pollutants from industries are SO2, CO,
CO
2, H2S and hydrocarbons together with dust, smoke and grit. These are produced
by the burning of coal and petroleum and by the combustion of lignite at thermal
power stations. The chemical industries release HCl, chlorine, nitrogen oxide and
oxides of copper, zinc, lead and arsenic.
The fertilizer factories at Gorakhpur and Ahmedabad; the steel industries at Bhilai,
Rourkela, Jamshedpur and Durgapur pollute the air with above-said gases.
(ii) Automobile Exhausts. Automobiles run by petrol and diesel produce CO, nitrogen
oxides and hydrocarbons. Hundreds and thousands tons of hydrocarbons and CO
are emitted into air daily. Metropolitan cities harbour lakhs and crores of
automobiles. Every gallon of petrol consumed by automobiles produces 3 pounds of
carbon monoxide and 15 pounds. of nitrogen oxide.
(iii) Ionizing Radiations from Radioactive Substances. Ionizing radiations include alpha,
beta particles and the gamma rays etc. These are produced by atomic explosions
and testing of atomic weapons.
Effects of Air Pollution
Effect on Plants
(i) SO2 causes chlorosis and also results in the death of cells and tissues.
(ii) Fluorides and PAN damage leafy vegetables such as lettuce and spinach.
(iii) Oxides of nitrogen and fluorides reduce crop yield.
(iv) Smog bleaches and blaze foliage of important leafy plants.
(v) Hydrocarbons cause premature yellowing, fall of leave and flower buds, discoloration
and curling of sepals and petals.
(vi) Smoke and dust cover the leaf surface and reduce photosynthetic capacity of plants.
(vii) Ozone damages cereals, fruits, and cotton crop.
Effect on Man
The effect of pollutants on animals and man are as follows-
(i) Ozone causes dryness of mucous membranes, changes eye vision, causes headache,
pulmonary congestion and oedema.
(ii) Ozone has been reported to produce chromosomal aberrations.
(iii) SO2 causes drying of mouth, scratchy throat, smarting eyes and disorders of
respiratory tract.
(iv) SO3, CO and NO2 diffuse into blood stream and reduce oxygen transport. CO
damages cardiovascular system. Hydrocarbons and other pollutants act, as
carcinogens and lead to different cancers.
(v) Cotton dust leads to respiratory disorders e.g. bronchitis and asthma.
(vi) Smoking of tobacco causes cancerous growth in lungs.
Change in Climate
CO
2 content of air is increasing due to deforestation and combustion of fuel. This
increase is affecting the composition and balance of gases in the atmosphere. Increase in
CO
2 concentration may increase the atmospheric temperature, producing green house effect
A rise of global temperature by more than 2-3 degrees may melt glaciers and polar ice. This
would lead to a rise in ocean level and consequent flooding and submergence of coastal
areas. Rainfall pattern may also change, affecting agricultural output in various regions of’
the world. Aerosols deplete the ozone layer in the stratosphere. Thinning of ozone layer
would permit more of the harmful ultraviolet rays to reach the earth. This may cause,
sunburn, blindness and inactivation of proteins, RNA, DNA and plant pigments.
Aesthetic Loss
Dust and smoke spoils the beauty of nature. Especially the mountain environments,
which serve as a great attraction for tourists. Foul odours emitted by industries, automobiles,
dirty drains and garbage heaps in cities are a great nuisance.
Control of Air Pollution
Following measures have been suggested to control air pollution-
(i) Some gases, which are more soluble in a particular liquid than air, for example,
ammonia in water, can be separated by dissolving in it
(ii) Particles larger than 50 mm are separated in gravity settling tanks. Using cyclone
collectors or electrostatic precipitators separates fine particles.
(iii) The height of chimneys should .be increased to the highest possible level to reduce
pollution at the ground level.
(iv) SO2 pollution can be controlled by extracting sulphur from the fuel before use.
(v) Pollution control laws should be enforced strictly.
(vi) Trees should be planted on the roadside, riverbanks, parks and’ open places as they
keep the environment fresh.
(vii) Population growth, which is the main cause of pollution should be checked.
(viii) Nuclear explosions should be restricted.
Water Pollution
Water is extremely essential for life, this common fact is known to all. It is required to
meet our basic needs in day to day life viz., cooking, drinking, bathing, disposal of sewage,
irrigation, generating electricity in power plants, cooling and manufacturing different products
in industries and the disposal of industrial wastes. During all these processes the undesirable
substances are added to the water resources to a great extent. This alters the basic chemistry
of water in rivers and streams.
<<< Previous Next >>>
Comments
Post a Comment